Printed circuit boards are basic components of electronic products. Printed circuit boards are classified into two sorts according to their substrates: rigid printed circuit boards and flexible printed circuit boards. The rigid printed circuit board is principally applied in a motherboard or a peripheral card of a computer, a communication product, such as a board of a mobile phone, or a board of a consumer product. The flexible printed circuit board is widely used, and the flexible printed circuit board can be divided into four sorts according to functions: lead line, printed circuit, connector, and integration function system.
The basic portion of a flexible printed circuit board is a film, which is used to support circuits composed of copper pieces. Because the flexible printed circuit board has properties of lightness, soft, thinness, smallness, ductility, flexibility and high wiring density, the flexible printed circuit board can be three-dimensionally wired and the shape of the flexible printed circuit board can be changed according to space limitations. The flexible printed circuit board is therefore typically applied in tiny products, such as notebook (NB), mobile phone, personal digital assistant (PDA) and information appliance (IA). For example, the flexible printed circuit board can be used as a connection between a liquid crystal display (LCD), a floppy disk driver (FDD), a hard disk driver (HDD) or a compact disc read only memory driver (CD-ROM) to a motherboard; a connection between a component, such as slot or far-infrared ray transmission, to a motherboard in a high-end level notebook; tone push-buttons of a mobile phone or a personal digital assistant; and a connection between a microphone or numeral keys and a panel of a liquid crystal display.